Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Maxwell Technologies (NASDAQ:MXWL) jumped nearly 10% today after the company announced it is supplying ultracapacitors to ABB (NYSE:ABB).

So what: Specifically, Maxwell's ultracapacitors will be used by ABB under its recently won contract to upgrade Philadelphia area rail lines. By incorporating Maxwell's technology in a hybrid version of its battery-based ENVILINE braking energy recuperation system, ABB was able to both increase the system's efficiency and extend battery life.

Now what: Shares of Maxwell have risen more than 40% since the beginning of March, a rise punctuated by a 23% pop amid rumors of an impending partnership with Tesla and the expansion of Maxwell's ultracapacitor-based Engine Start Module to medium-duty-trucks. Maxwell's press release today also highlighted the usefulness of its ultracapacitors in braking energy recuperation systems for electric and hybrid vehicles -- a move likely to spur even more speculation of new partnerships going forward. Even so, given the risk of those partnerships not coming to fruition and with shares trading around 72 times next year's expected earnings, I'm not particularly anxious to dive in today.

Steve Symington has no position in any stocks mentioned. The Motley Fool recommends and owns shares of Amazon.com. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.